AP-IP230 IP Phone Installation Guide Version 1.0
AddPac Technology Proprietary & Documentation
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available communications path that connects two fixed end points.
Q.931 Signaling
ITU-T specification for network layer of ISDN. Q.931 uses out-of-band
signaling on the D-channel to control calls.
QoS
This refers to the assumption that data transmission rates, error rates, and
other characteristics can be measured, improved, and to some degree,
guaranteed in advance. Basically, QoS describes a collective measure of the
level of service a provider delivers to its customers or subscribers.
RAM
Random-Access Memory, a non-retentive memory, whose contents get lost
after a switch-off or reset. Application programs run in the random access
memory and data is stored and processed.
RAS
Registration Admission Status protocol. The communication protocol used to
convey registration, admission and status messages between H.323 endpoints
and the gatekeeper.
RISC
Reduced Instruction Set Computing
Router
On the Internet, a router is a device or, in some cases, software in a computer,
that determines the next network point to which a packet should be forwarded
toward its destination. The router is connected to at least two networks and
decides which way to send each information packet based on its current
understanding of the state of the networks it is connected to. A router is
located at any gateway (where one network meets another), including each
Internet point-of-presence. A router is often included as part of a network
switch. Compare with: gateway. Refer to: relay.
RS-232
Most common Physical Layer interface. Known as EIA/TIA-232.
RTCP
Real-time Control Protocol (RTCP) is a companion protocol of RTP that is
used to maintain quality of service. Refer to: RTP(Real-Time Transport
Protocol).
RTP
1. Routing Table Protocol, VINES routing protocol based on RIP. Distributes
network topology, and aids VINES servers in finding neighboring clients,
servers, and routers. Uses delay as a routing metric. Refer to: SRTP.
2. Rapid Transport Protocol. Provides pacing and error recovery for APPN
data as it crosses the APPN network. With RTP, error recovery and flow
control are done end-to-end rather than at every node. RTP prevents
congestion rather than reacts to it.
3. Real-Time Transport Protocol. Commonly used with IP networks. RTP is
designed to provide end-to-end network transport functions for applications
transmitting real-time data, such as audio, video, or simulation data, over
multicast or unicast network services. RTP provides such services as payload
type identification, sequence numbering, time-stamping, and delivery
monitoring to real-time applications.
